nushell/crates/nu-cmd-dataframe/src/dataframe/eager/query_df.rs
Stefan Holderbach b19da158d5
Rename Value::CustomValue to Value::Custom (#12309)
# Description
The second `Value` is redundant and will consume five extra bytes on
each transmission of a custom value to/from a plugin.

# User-Facing Changes
This is a breaking change to the plugin protocol.

The [example in the protocol
reference](https://www.nushell.sh/contributor-book/plugin_protocol_reference.html#value)
becomes

```json
{
  "Custom": {
    "val": {
      "type": "PluginCustomValue",
      "name": "database",
      "data": [36, 190, 127, 40, 12, 3, 46, 83],
      "notify_on_drop": true
    },
    "span": {
      "start": 320,
      "end": 340
    }
  }
}
```

instead of 

```json
{
  "CustomValue": {
    ...
  }
}
```


# After Submitting
Update plugin protocol reference
2024-03-27 22:10:56 +01:00

105 lines
2.9 KiB
Rust

use crate::dataframe::{
eager::SQLContext,
values::{Column, NuDataFrame, NuLazyFrame},
};
use nu_engine::command_prelude::*;
// attribution:
// sql_context.rs, and sql_expr.rs were copied from polars-sql. thank you.
// maybe we should just use the crate at some point but it's not published yet.
// https://github.com/pola-rs/polars/tree/master/polars-sql
#[derive(Clone)]
pub struct QueryDf;
impl Command for QueryDf {
fn name(&self) -> &str {
"dfr query"
}
fn usage(&self) -> &str {
"Query dataframe using SQL. Note: The dataframe is always named 'df' in your query's from clause."
}
fn signature(&self) -> Signature {
Signature::build(self.name())
.required("sql", SyntaxShape::String, "sql query")
.input_output_type(
Type::Custom("dataframe".into()),
Type::Custom("dataframe".into()),
)
.category(Category::Custom("dataframe".into()))
}
fn search_terms(&self) -> Vec<&str> {
vec!["dataframe", "sql", "search"]
}
fn examples(&self) -> Vec<Example> {
vec![Example {
description: "Query dataframe using SQL",
example: "[[a b]; [1 2] [3 4]] | dfr into-df | dfr query 'select a from df'",
result: Some(
NuDataFrame::try_from_columns(
vec![Column::new(
"a".to_string(),
vec![Value::test_int(1), Value::test_int(3)],
)],
None,
)
.expect("simple df for test should not fail")
.into_value(Span::test_data()),
),
}]
}
fn run(
&self,
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
command(engine_state, stack, call, input)
}
}
fn command(
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
let sql_query: String = call.req(engine_state, stack, 0)?;
let df = NuDataFrame::try_from_pipeline(input, call.head)?;
let mut ctx = SQLContext::new();
ctx.register("df", &df.df);
let df_sql = ctx
.execute(&sql_query)
.map_err(|e| ShellError::GenericError {
error: "Dataframe Error".into(),
msg: e.to_string(),
span: Some(call.head),
help: None,
inner: vec![],
})?;
let lazy = NuLazyFrame::new(false, df_sql);
let eager = lazy.collect(call.head)?;
let value = Value::custom(Box::new(eager), call.head);
Ok(PipelineData::Value(value, None))
}
#[cfg(test)]
mod test {
use super::super::super::test_dataframe::test_dataframe;
use super::*;
#[test]
fn test_examples() {
test_dataframe(vec![Box::new(QueryDf {})])
}
}